Question

In an electrical circuit, the voltage across a resistor is directly proportional to the current running through the resistor. If a current of 12 amps produces 480 volts across a resistor, how many volts would a current of 1.5 amps produce across an identical resistor?

Answer 1

1st case:

Current(I)=12 A

Voltage across resistor(R)=480 V

Let R be the resistance given by resistor

We know ,

R=V/I=480/12=40 ohm

2nd case:

Current(i)=1.5 A

Resistance(R)=40 ohm [As the resistance of the 1st and 2nd cases are identical]

Voltage across resistance(v)=iR=1.5 x 40=60 V

Answer:60 V

Hope this helps:)

Answer 2

Given:

Current (I₁) = 12 A

Potential difference (V₁) = 480 V

Current (I₂) = 1.5 A

To find:

Potential difference across the 2nd circuit.

Solution:

• Ohm's law states that the current flowing through a conductor is directly proportional to the potential difference applied across its end.

In, first circuit, we have been given current and voltage, Hence, applying Ohms' s law , we get

$V = IR$    $;$ $or$

$R = \frac{V}{I}$

$R = \frac{480}{12}$

Hence, $R = 40$Ω

Also, we have been given that an identical resistor is connected across 1.5 A circuit.

Hence,

$V = IR$

$V = (1.5)(40)$

$V_{2} =60V$

Final answer:

Hence, Potential difference of 60V is to be applied for an output current of 1.5A given, the applied resistor is of 40Ω .